Machine for utilizing power



J. 5. PARENTI 2,391,476

MACHINE FOR UTILIZING POWER Dec. 25, 1945 5 Sheets-Sheet 1 Filed May'19, 1942 ATTORNEYS Dec; 25, 1945. J. 5 ENT 2,391,476

MACHINE FOB UTILIZING POWER Filed May 19, .1942 5 Sheets-Sheet 2ATTORNEYS 4 D 5 945- J. s. PARENT. 6

MACHINE FOR UTILIZING POWER Filed May 19, 1942 '5 Sheets-Sheet s I I)fiOR X g @402, 0M aim 4'5 V I 57 ATTORNEYS Dec. 25, 1945. J. 5. PARENTI7 v MACHINE FOR UTILIZING POWER r I Filed May 19, 1942 Y 5 Sheets-Sheet4' ATTORNEYS 25, 1945. J. 5. PARENT] MACHINE FOR UTILIZING POWER FiledMay 19, 1942 5 Sheets-Sheet 5 mitt-Dill!!! 0555i Rog/Z ,a 'ram/z.

ATTORNEYS Patented Dec. 25, 1945 UNITED STATES PATENT OFFICE l MACHINEFor: UTILIZING POWER Josephf S. Parenti,.Buffalo, N. Y. ApplicationMay19, 1942, Serial No. 443,666

19 Claims. (c1.23o177) This invention relates to improvements inmachines of the sliding piston or positive displacement type, which maybe used, for example, as compressors or pumps to operate on air andother gases. I

One of the objects of this invention isto provide a machine of this typewith means of improved construction for reducing side thrust of pistonson their cylinders. A further object of this invention is to provide animproved construction, in which the angular-relationship between thepistons and their connecting rods. is small when these parts aresubjected to their greatest stresses.

A further object of this invention is to provide a machine of this kindwith means of improved construction for cooling the same, whereby largeamounts of heat can be readily removed from the machine. Another objectis to provide a machine-of this kind in which heat is removed by aircirculating within the'pistons. A further object is to provide a machineof the revolving cylinder type in which the pistons extend beyond theouter ends of the cylinders and are provided with air passages throughwhich air passes because of the movement of the pistons relatively tothe surrounding air.

Another object of this invention is to provide a compressor of this kindof improved and simplified construction and of high efiiciency.

A further object of this invention is to provide an improved method ofcompressing gas in which residual compressed gas left in a compressingmember after exhaust, is added to gas at a lower pressure which is aboutto be compressed.

It is also an object of this invention to provide compressors with meansfor injecting a supercharge of gas into a cylinder after completion ofits intake stroke. A further object is to provide a compressor of thistype with means whereby residual compressed gas remaining in a cylinderafter the closing of the discharge valve is added to a charge of gas ata lower pressure,

and which is about to be compressed. Another object of thisinvention toprovide single or integral supports which carry both a cylinder wheelbearing and piston rod bearings, so that the forces resulting from themovements of the pistons in their cylinders will reactwithin suchsupports. A further object of this invention is to provide a compressorof the revolving cylinder type with means of improved construction forcooling the cylinders. A further object is to provide a compressor ofthis type with means of improved construction for circulating coolingair through the housing of the compressor and to the parts of thecompressor requiring cooling. A further object is to so construct thecompressor that the cooling air may be filtered or cleaned to preventabrasive particles from entering the compressor housing. Itis also anobject of this invention to so construct a. compressor that therevolving of the cylinders produces a flow of cooling air through thehousing of the compressor. It is also an object to provide connectingrods which ar shapedso as to produce movement of air toward theexteriorsurfaces of the cylinders for cooling them. v

It is also an object of this invention to provide an improved piston foruse in connection with compressors of this type. A further object ofthis invention is to provide a piston in which'the head of the'piston isso arranged relatively to the otherparts of the piston as to facilitatecooling thereof and to resist the passage of heat from'the head of thepiston to the other parts of the piston. Another object of thisinvention is to improve the construction of pistons to facilitate thecooling of the same.

It isalso an object of this invention to provide an improved process ofcooling machines of this type by removing more heat from the pistonsthan from the cylinderwalls.

Another object is to provide a machine of this type with means forpurifying the air employed for cooling the machine.

It is also an object of this invention to improve the construction ofgas compressors of the rotary cylinder type in such a manner as toprovide ior improved and more efficient compressing of gas.

f Other objects. of'this invention will appear from the followingdescription and claims.

In-the accompanying drawings:

Fig; l is anx-end elevation, partly in section, of acompressor embodyingthis invention.

Fig. 2'is a fragmentary end elevation of the other end of the compressoralong line 2-2, Fig.

3, on a larger scale, the discharge tube of the compressor being shownin section.

Fig. 3 is a fragmentary, sectional elevation thereof on line 33, Fig. 1.

Fig. 4 is a fragmentary, sectional elevation thereof on line 44, Fig. 3.

Fig. 9 is a fragmentary perspective view of the valve of the compressor.

Fig. 10 is a central, sectional elevation of a piston, the section beingtaken on line Ill-10, Fig.3.

Fig, 11 is a sectional elevation of the piston on line l'l-l I, Fig. 10.

Fig. 12 is a top plan. view thereof.

Figs. 13 and .14 are transverse sectional views thereof on lines I3-13and I l-l4 respectively of Fi 11.

Fig. 15 is a diagram showing the relative angular relations between thepistons and their connecting rods while in different positions about theaxes of rotation of; the cylinders and of the eccentric ring to whichthe connecting rods are pivoted.

While I have shown my improvements embodied in a rotary cylinder type ofcompressor, yet it will be obvious that it is not intended to limit allof the improvements herein described to the type of compressor shown inthe drawings, since some of the improvements shown may be used inconnection'with machines for other purposes than compressing gases andwith machines in which the cylinders are stationary.

My improved machine may be'mounted on any suitable or desired stationarysupports and may be enclosed in a'housing or casing of any desiredconstruction. In the particular construction illustrated by way ofexample, I have provided a housing or enclosure, including a lower partand an upper, removable part or cover 2|, which may be suitably securedto the main or lower housing part 20. The lower housing part is alsoprovided at its opposite ends with integrally formed pedestals orsupports for the revolving parts of the machine, these pedestalsincluding two pairs of upright struts or flanges 22 which may be formed.integral with the housing and which are connected at their upper ends bysubstantial horizontal webs or flanges 23 formed to support themechanism. A housing and supports of any other suitable or desiredconstruction may be employed, if desired.

The machine shown in the drawings includes two revolving parts whichrotate about different axes. In the particular construction shown, thecylinders rotate about an axis which is eccentric with reference to arotary member which the piston rods are connected to, to producerelative movement between the pistons and their cylinders. I provide ateach end of the machine a main stationary bearing support 25 on whichthe two revolving elements of the machine are journalled and which, inturn, is mountedupon the pedestals or supports 22. Consequently, eachend of the machine is provided with one of these bearing supportingmembers 25 which are of tuprojections 26 arranged to be mounted on thesupporting flanges 23 of the pedestals 22. The .bearing supportingmembers 25 are each provided with an annular cylindrical portion orflange 21 within which a suitable bearing, such as a roller bearing 28,is arranged. Each bearing support is also provided with a cylindricalportion 29 of larger diameter and eccentric with relation to the bearingflange 21. Another bearing 30 is arranged on the periphery of thecylindrical portion 29. These two flanges or cylindrical portions areconnected by a vertical web 3|. 32 represents an annular flange which isconnected by means of radially extending ribs or supporting bularformand have oppositely exten'dinglugs or parts 33 with the cylindricalflange 29. The several parts of each bearing support are preferablyformed integral, thus forming a strong and rigid bearing support whichis amply capable of withstanding the reacting forces transmitted thereto.by the bearings 28 and 30.

The bearings 2-8 of the two bearing supporting members 25 have theirinner races 35 secured to rotatable hollow trunnions or shafts 36 and 37which extend freely through the stationary bearing supporting members.The inner ends of these trunnions are suitably secured to'acylinder-carrying member or wheel with which the cylinders arepreferably formed integral and which includes a plurality of cylinders38 connected by radially extending Webs 39 and also preferably by aseries of radiating and reinforcing fins 40 which are substantiallyannular in form and concentric with the axis of rotation of the Cylinderwheel. The trunnions 36 and 31 may .be secured to the cylinder wheel inany suitable or .desired manner, and in the construction shown, theinner ends of the trunnions. are provided with outwardly extendingflanges 4| which may be secured by bolts or other means to the cylinderwheel, see particularly Fig. 3. Consequently, the cylinder wheel isrotatably mounted on the bearings 28, and one of the hollow trunnions,for example the trunnion 36, may be provided at the outer end thereofwith any suitable means for driving the cylinder wheel, a grooved pulley42 being shown by way of example in Fig. 3. v

The cylinders are provided with pistons 44 which will be hereinafterdescribed more in detail. Thesepisten-s may be reciprocated in theircylinders in any desired-manner, and in the construction illustrated byway of example, the pistons have pins extending transversely through thesame near the outer ends thereof. These pins &5 also extend outwardlybeyond the sides of the cylinder Wheel, this wheel being provided at thecylinder portions-thereof with slots 45 into which the pins 45 may enterwhen the pistons are in their inner positions. Oneach end of each pin45',v one end of a piston rod or link 48 is journalled on suitablebearings 49', and the other ends of the piston rods or links 48 arepivoted on master rings which are journalled to rotate about thebearings 30-, eccentrically with reference to the axis of rotation ofthe cylinder wheel. In the particular construction shown, these. masterrings are each constructed of two parts or halves El and 52,. securedtogether by means of screws 53. which also serve as pivots for the otherends of the piston rods or links. Suitable bearingsv 54 are arrangedbetween the pins 5.3 and the inner ends ofthe connecting links or rods.The master rings are arrangedat the oppositev sides of, the cylinderwheel, and. since the master rings. rotate about the. bearings, whichare eccentric with referenceto the bearings 28 f the cylinder wheel,

itwill be obvious that at each rotation of the cylinder and masterrings, the. pistons M will be moved by. their. piston rods 48 through animwardly directed working stroke and an outwardly directed intakestroke.

In order to cause the master rings'and cylinder wheel to rotate abouttheir axes simultaneously and in correct relation to each other, asuitable connection between these parts is provided. In the constructionillustrated by way of example, I have provided the outer portions 52ofthe eccentric master rings with a plurality of outwardly extendingarms 56, four such arms being'shown in Fig. 4. To the outer end of eachof these arms, one end of a master ring link '1 is pivote allyconnected. The. other ends of these links are pivotally connected withthe cylinder wheel. This may be accomplished in any desired manner, andin the construction shown, the cylinder wheel is provided between someof the cylinders with enlargements or bosses 58 in which pins 59 arearranged, the pins being preferably journalled in these :bosses.The'ends of the pins are secured to the other ends of the master ringlinks 51. It will be noted thatduring the rotation of the master ringsand the cylinder wheel, the links5l occupy various positions, as shownin Fig. 4, and when these master ring links are in or near a planepassing through the two axes of rotation, no driving force can betransmitted through such links, but at such times the other links arenotlocated near this plane and will transmit the necessary force fordriving the master ring from the cylinder wheel, which is positivelydriven from the pulley 42 or other driving means. The distance'betweenpivotal centers of the master ring links 51 must be the same as thedistance between the axes of the cylinder wheel and the master ring. Bymeans of this arrangement, the relationship between all of the cylindersand their pistons will be the same as they pass any point in their pathof movement about the center of rotation of the cylinder wheel, and alsothe connecting rods on both sides of the cylinder wheel are kept inalinement with each other so that the resultant of the force transmittedby a pair of rods to its piston is substantially coaxial with thepiston, which, in turn, results in elimination of any cocking or wedgingaction on the pistons and of any tendency to turn-or twist the pistonsabout their axes. a

, In order to supply as to be compressed to the cylinders and todischarge the compressed gas from the cylinders, a tubular member isprovided having both an inlet passage and a discharge passage therein,the member shown including an inlet duct 60 which extends through thehollow trunnion 36 and a discharge duct Bl which extends through thehollow trunnion 31. These inlet and exhaust ducts are preferably formedintegral with a valve member 62 arranged for cooperation with thecylinder wheel at the inner ends of the cylinders 38. This tubularmember including the valve 62, as well as the ductsBfl andGl, in'theparticular construction shown, is

stationary with reference to the cylinder wheel,

and the valve member is of frusto-conical shape. The valve member isprovided with a relatively large inlet port63 which forms substantiallya continuation of the inlet duct or passage 60 and a smaller exhaust ordischarge ort 64 which forms a continuation of the discharge ductBl.Both of these ports are of elongated form in order to. cooperate withelongated ports formed at the inner ends of each ofv the cylinders- Thedis-.

charge duct 6| may of course be of smaller diameter than the inlet duct,and this enables the discharge duct tobe spaced from the trunnions 31.

This space between theduct and the trunnion resists .the transmission ofheat from the hot duct 6| to the-trunnion bearing- If desired, suitableheat insulation may be provided in the space betweenthis ductand thetrunnion.

.The middleportion of the cylinder wheel is provided with afrusto-conical bore formed for close fitting cooperation with the valvemember 62, and the cylinder wheel is provided at the opposite ends ofits frusto-conical bore with annular imperforate sealing surfaces 66 and61 which fit against corresponding surfaces 68 and 69 formed on thevalve member so that when the valve is in its, operative position,discharge of gases past the cooperating sealing surfaces is prevented.The cylinder wheel is provided at its frusto-conical valve-engaging basewith an elongated port Ill for each cylinder. The opposite longerbounding edges of these ports 10 are arranged at an inclination to eachother because of the frusto-conical form of the valve member, so thatall portions of any longitudinal edge of any of the ports 10 willsimultaneously come into and pass out of registration with thelongitudibase of thecylinder wheel.

nal edges of the port 63 and 64 of the valve member, thus reducing wiredrawing to a minimum at the discharge ports.

In order to produce discharge ports of this narrow elongated type, thecylinders are provided at their inner end, portions with converging sidewalls which are formedto converge uniformly from their outer portions ofcylindrical cross section to the valve ports 10 thereof. Consequently,the side portions H of the cylinder ends which are nearest to adjacentcylinders are preferably substantially flat, see also Figs. 6 and 7.This makes it possible to provide a relatively large number of cylindersin the cylinder wheel, and at the same time keep the valve 62 ofrelatively small diameter. The cylinders in the construction shown areprovidedin their cylindrical portions with cylinder sleeves l2 rigidlysecured thereto, which may be of a material differing from the materialof which the cylinder wheel is made. For example, the cylinder sleeves12 may be of cast iron and the cylinder Wheel may, if desired, be madeofv a. light weight metal or alloy.

By means of the construction of the valve and valve ports, the ports,because of their elongated shape-,havethe desired cross sectional areaand, at the same time, the frusto conical valve member is ofcomparatively small diameter, so that the lineal speed of the frustoconical portion of the revolving cylinder Wheel with reference to thestationary valve, is kept small enough to avoid excessive wear ofthesecontacting surfaces.

The stationary valve may be maintained in tight seating relation to thefrusto conical inner portion of the cylinder wheel in any suitable ordesired manner, and preferably, this is accomplished by yieldinglyurging the valve member and its inlet and discharge passages inalengthwise direction to seat the valve member in the For example, in theconstruction illustrated, the discharge duct 6| of the valve member isprovided'with an outwardly extending flange 14 suitably secured to thedischarge duct'6l, for example, by means of a screw threaded connection,as shown, and this flange .14 is yieldingly urged to the left in Fig. 3,by means of. springs 15. extending about bolts or studs'li which arescrewedinto a stationary diskor port Hot the machine. This II also.serves the purpose of holding the bearing 28 in place, as clearly shownin 3. .A similar bearing-rm taming disk .7 8 is provided at: theopposite end :of the machine, which is held in place by nuts :or studs79, Fig. l, which engag'ein threaozled holes in theicylindrical portionor flange 2:! of the :stationary bearin support 25, and similarstuds orscrews (not shown) may be used for securing the disk. 18 'tothe otherstationary bearing shaft on the discharge end "of the machine.Conseuerrtly, springs 15 urge the flange '14 to the left in Fig. 3 andurge the valve into seating ongagement in the bore of the cylinderwheel. Nuts 80 are adjustably mounted on the studs 16 to permit varyingthe pressure with which the valve is urged into seating engagement withthe bore of the cylinder wheel, so that the pressure of the springs canbe varied, depending upon the pressure of the fluid discharged from thecylinders.

The valve. construction described is desirable for the reason that thesprings automatically compensate tor wear of the valve or of the metalat the bore of the cylinder wheel.

FI'heilange l tand thestuds 16 may alsobe used to hold the tubularmember and the valve against turning with the cylinder wheel. For thispurpose, the flange 1 4 may be: provided with slots 81, Figs. 2 and 3,into which the ends of the studs 16 extend. Since during the rotation-ofthe cylinder wheel, these studs will bear against one side only of theslots, the studs are preferably provided with flat sides which bearagainst the sides M :of theslots,-

which they will engage during the rotation of the cylinder wheel, :andthe slots are also: formed so that each side 82 lies substantially inaradial plane: extending through the center of rotation of the cylinderwheel. Consequently, the studsl6 oppose force tending to turn the flange14 without producing radial components of this force. The slots M arealso made long enough and. wide enough to permit any slight movementthat may be imparted to the discharge duct 6-! because of inaccuraciesin machining.

'83 repirisents a pipe or tube which conducts the compressed :gas fromthe discharge duct- 81, and which in the construction shown has a flangewhich is securedto' the flange 14. This tube 83 is preferably.flexibleto: allow tor-any slight movement ofithe duct 6|.

In the operation of the compressor as thus far described, when: power isapplied to rotate the trunnion 36, the cylinder wheel rotates about itsaxis. Through the medium of the master ring links 51, rotary motion isimparted from the cylinder wheel to the eccentric master rings arranged.at opposite sides of the cylinder wheel and mounted on the bearingswhich are eccentric with relation to the axis of rotation. oi thecylinder wheel. Gonsequently, thepistonswill be caused to reciprocate intheir cylinders, some of the various positions of the pistons beingshownain.Flg. -4. In.v the machine illustrated inv the drawings, theaxis of rotation of the cylinder wheel is located vertically above theaxis of rotation of the master ring and, consequently, a cylinderreaches approximately the upper of the machine, its piston will be inits innerposition. Assuming that rotation is in. a clockwise directionin Fig 4, each piston, as it moves with the cylinder wheel from theupper position, will move outwardly, and will move. into communicationwith the. last inlet port 63 of the valve member. When it reaches thelower portion of. its

movement, the piston will be in. its outermost position, and. from thenon to. its upper position, it will be moved inwardly in its cylinder tocom.- press the gas taken in- During a part of the time that a cylinderpasses through the upper, lert quadrant in Figs. 4, 6, 7 and 8, its portmoves into registration with the discharge port 64 :of the stationaryvalve, thus discharging the compressed gas into the discharge duct 6|.Consequently, it will be noted that the greater portion of the work doneby each piston will be in. the upper, left 'quadrant of Fig. 4, and themaximum power is required by the piston during this portion of itsstroke. It will also be noted that very little side thrust is appliedtothe pistons by the piston rods 48 during the intake or suctionstrokewhich takes place during the movement of the piston from the upper tothe lower position, since centrifugal force will act on the pistons in adirection to move them rad-ially'outwardly. This is due to the fact thatthe axes of the pistons and cylinders extend radially from the axis ofrotation of the cylinder wheel, so that the centrifugal force acting onthe pistons produces no side thrusts of the pistons on the cylinders. Itwill also be noted that the piston rods '08 will occupy positions inangular relation to the axesoi their cylinders and pistons in all buttwo points of their path of rotation, namely, when the piston rods 48are in radial planes of the cylinder wheel, i. e. in planes in which theaxis of rotation of the cylinder wheel lies. Consequently, the pistonrods will tend to produce side thrusts on the pistons during allportions of their paths of movement except at said two points when thesepiston rods are in said radial planes of the cylinder wheel, the extentof the side thrusts depending upon the size of the angle between saidradial planes and the piston rods, and upon the amount of forcetransmitted by the rods to the pistons. Since these side thrusts resultin wear on the pistons-and cylinders, it is desirable to reduce them toa minimum.

I have found that these side thrusts can be greatly reduced bypositioning the master ring with reference to the cylinder wheel in sucha manner that the piston axes will lie in the same plane as the centersof the piston rods 48, i. e.,

in dead'center positions, when the pistons are subjected to high gaspressure. This can be accomplished by so connecting the master ring tothe cylinder wheel by means of the master ring links '51 that the masterring will be slightly in advance of the cylinder wheel in the directionof rotation. In other words, if it be assumed that the normal positionof the master ring would be such that the piston rods lie in the planesof the axes of the pistons, when the pistons are in their uppermost andlowermost positions, and assuming that the cylinders, when in theiruppermost positions have just been disconnected from the discharge port64 of the valve, then according tomy invention, I secure the master ringtothe cylinder wheel in such manner that the master ring will be inadvance of such normal position in the direction of rotation. The extentto which the master ring may be advanced depends upon several factorsand, consequently, may vary considerably, and in the construction shownvby way of example in Figs. 4 and Y15, the master ring is shown asadvanced seven degrees. The effect of this advance will beapparent uponinspection of Fig. 1 5, in which 84 represents the center or axis ofrotation of the cylinder wheel and 85 the center or axis of rotation ofthe master rings. In this figure the positions of the: piston rods areair which can be admitted to the cylinder during shown diagrammaticallyat intervals of by the lines 86, connecting the pivot pins 53 of themaster ring with the pins 45 of the pistons; Any

radial line,'such as lines 81, drawn from the center 84 to a pin 45 willindicate the axis or center line of the pistonin such position, and theradial planes of the cylinder wheel. It will be noted on thisdiagramthat at the left half of the path of movement of the pistons,-inwhich they require the most power, the anglesbetween the radial planesof the cylinder wheeland the piston rods, i. e. between lines 81 and 86,are much less than in the right half of the diagram, in which the forcestransmitted by the piston rods to the piston are the least. It will alsobe noted that" radial planes 81 and piston rod lines 86- wi ll coincideat a point somewhat less than 30 from the vertical at the'top of thediagram, at which point the pressure of the compressed fluid in thecylinder is approximately at the maximum, and consequently, at thispoint there will be no side thrust on the'piston. At either side of thispoint; the angle between lines 86 and 81 will be very small, so that theside thrusts at these points willlbe correspondingly small.

' It willalso be noted from Fig. that the positions in which the pistonrods are in the radially planes of the cylinder wheelare in the lefthalfof the path of rotation, and that the anglesrbetween the radial planes8! and the lines 86 are also smaller in this left half, and since' thegas pressures acting on thepistons in this half of their path ofmovement become increasingly greater, the smallness of these anglesresults in.

decreased side thrusts. The construction described consequently jresults in the pistonrods passing through these radial planes 81 twicedurbe greater than they would beif the master ringhad not been advanced.Since, ,however, very little power is'transmitted to the pistons by theconnecting piston rodsat this right half of the path, correspondinglysmall side thrusts will be produced in this half of the path. j If itshould happen that centrifugal force alone is sufficient to move thepistons outwardl during their suction strokes, then no power would betransmitted by the piston rods 48, and no side thrusts would result,regardless of the angular relation between the lines 86 and B'L'becauseof the fact that the axes of the cylinders and pistons are radial withreference to the axis of rotation of the piston wheel. Even ifcentrifugal force does not full eliminate side thrusts, it willnevertheless greatly'reduce such side thrusts as occur at the right halfof the path of movement of the pistons. The arrangement describedconsequently materially reduces the wear on the pistons and cylindersresulting from sidethrusts produced by the piston rods.

In compressors as "now commonly constructed,

the residualcompressed gas which remains'in a cylinder "after theclosing of the discharge valve,

the volume of which depends upon the clearance between the head of thepiston and the head of the cylinder, is re-expanded during the initialportion of the intake stroke of the piston, and consequently, thisreduces the fresh charge of the intake stroke. I

In accordance with my invention, I provide an improved method and meanswhereby this residual gas is discharged into a cylinder in which thepiston has just completed its intake, and in which the intake valve isclosed. This residual gas, consequently, supercharges the cylinder intowhich it is discharged, so that this cylinder will compress not only thecharge. of gas taken duringthe suction or intake stroke, but also suchresidual gas as is delivered to it.

Any suitable or desired means may be employed for carrying out mymethod. In the machine shown in Figs. Ho 9, this method can readily becarried out by providing a single relatively small passage through thevalve '62, for example.

such'as the passage S ll, shown in Figs. 3and 6-9. It will be noted thatthis passage, which in the construction shown may be in'thej form of a:hole drilled in the valve ,62, is so arranged that.

any cylinder after its port passes out of registration with thedischarge port 64 of the valve, will momentarily pass intoregistrationwith one endof the passage 90. The other end of this passageIn Figs. 6 and 7, the upper cylinder is shown in I the position in whichit has just passed-out of registration with the discharge port 64 of thevalve and the lowest cylinder has just passed out of registration withthe inlet'port B3, and neither of' these cylinders has as yet passedinto com munication with the connecting passage 90.

Fig. 8 shows the positions of the cylinders after they have passedthrough a small arc beyond:

the positions shown in Figs. 6 and Land shows the upper cylinder inregistration with the upper end. of the passage 90 and the lowestcylinder also in registration-with the lower end of this passage.

Consequently, residual compressed gas in theiupper cylinder will quicklyflow through theipassa'gei 90 and will, consequently, beexpanded'iduri'ng this passage, and the'greater portion of thisresidualcharge will'be added to the charge of gas:

in the lowest cylinder, thus increasing the pres sure and the quantityofgas in the lowest cylinder and also greatly reducing the amount'ofresidual gas in the uppermost cylinder, so that when the'port'of thiscylinder moves into com munication with the inlet port 63 of the valve62,

it will take in a. materially larger charge of gas than would be thecase if it were first necessary to expand all of the'residual compressedgas re maining in the cylinder after exhaust. Conse.-

quently, by use of the supercharge passage, the

capacity of the compressor is increased, inthe' first place-because ofthe fact that with very:

littleresidual gas in the uppermost cylinder, this cylinder will take ona proportionately larger charge of fresh gas during its intake stroke.-The capacity of the machine is further increased by thevfact that thecylinder receiving the resid ual charge is supercharged and,consequently;' compresses a proportionately greater amountof' gas thanwould be the case if it had not been thus supercharged. Any other meansfor transferring residual compressed gas from a cylinder-to superchargea quantity of gas tobe compressed may be provided. I

Not only .does my improved methodg'reatlyin crease the capacity of anycompressor to which it" is applied,'buti also. the efficiency of the-compressor is greatly increased thereby. For e'xeach cylinder may be incommunication therewith for a longer period of time, without having theresidual compressed gas discharged into the intake passage, which wouldcause objectionable turbulence. of the incoming air. I preferablyconstruct the valve .so that the intake starts after the pressure in thecylinders is slightly below atmospheric, and since a number of cylindersare always in communication with the intakeport', there will be aconstant and steady flow of airin the inlet duct.

A further-advantage of the. removal of residual gas from a cylinder andemploying it to supercharge an intake of gas, is that this enablescompressors' to compress gases to much. higher pressures than hasheretofore been possible in .a single stage. Heretofore, the pressureswhich could.

beproduced in a. single stage were limited by the clearance between thecylinder heads and the pistons, or in other words, by the. amount ofresidual compressed gas lett a cylinder; If the pressure in .a cylinderreached a certain point at which the residual gas required the. fullstroke of the piston to become reexpanded, obviously no additional gascould be taken in and, consequently no: compressed gas. would. hedelivered. Conse-.

quently, heretofore, the maximum pressureinany cylinder had a definitelimitation. because of the expansion of the residual compressed gas. Bymeans or my 'methodand construction, since most of the residual gas isdischarged from the cylinden, it follows that only a very slight.-movement of. the. piston in the cylinder will expand the very smallquantity of residual gas left in the cylinder after .supercharging, andconsequently the maxi.- mum. gas. pressure that can be. delivered by anycy-linderisgreatly increased.

Because of the large amount of: heat. developed when the gas iscompressedl. provide. means; of improved construction for coolingthe-cylinder wheel and also the pistons. Ashas :beenstated, the cylinderwheel is provided with a. series of substantially circular fins 40 whichserve not only to reinforce the cylinder wheel, but also to facilitatethe transfer of heat. from the cylinderwheel. In order to induce a.flowof air into the spaces between the fins: during the rotation oi themachine, I construct the piston rods or links 48 in such manner thatthey act as vanes to deflect air againstthe cylinder wheel. For example,these piston rods may be provided. with .inclined faces 9.2.intermediate of their ends; these faces being shaped. so as to directair toward the cylinder wheeLsee particularly Fig. 5... The crosssectional shape of therintermediate portions of these: piston rods ispreferably of air foil or other suitable form to produce the maximummovement oi airtoward the cylinder-wheel. Since the piston rods. arelocated near the cylinder portions 38 of the wheel, it will be obviousthat. the air deflected by the; rodswill flow between. the annularwehsas: along the walls of the. cylinders and: into. the spaces betweenthe cylinders; so. as to bring about a very effective exchange of heatbetween. the cylinder wheel and the air. The factthat. these airdeflecting parts .of thepiston rods are of substantially air-foil shapealso results in. a suction or rarified air at the outer trailing ends ofthese sections, which results. in. drawing air out of the spaces betweenthe. fins: 40 toward the trailing edges of the: rods. thus producing a.turbulence and circulating effect in adjacent to the cylinder wheel. Thefact that the radial web .37 extends. between adjacent cyilinder walls,prevents air from being blown bythe' piston rods 48 from one side to theother of. the cylinder wheeland this web also assists in the transfer ofheat to. the circulating, air. The: fact that these piston rods. occupydifierent positions relatively to their cylindersat difierent portionsof their strokesalso improves the cooling effect by directing aircurrents to different. portions of the cylinder wheel during eachrotation. Other means for deflecting cooling air against the. sides ofthe; cylinderwheel may be employed if desired.

In accordance with mYlHVCHfiOH, I obtain, very superior cooling efiectsby circulating cooling air in the interior of the. pistons, By havingthe outer ends. of. the pistons.v extend beyond. the periphery of therotating, cylinder wheel, air can be circulated through the pistonsbecause of the rapid movement of the outer ends of the pistons throughthe surrounding .air.

The pistons employed in my improved compressor may be of any suitable.or desired. construction,'but in order to efiectively cool the same,they are preferably made hollow and. are each. provided. with a passagefor receiving and discharging cooling air at their outer portions, suchpassage receiving air at the portion of the piston which faces forwardlyduring the rotationof the piston with. the cylinder and dischargingheated air at. the rear or trailing portion of the piston. Consequently,the pressure of air at the front of the piston, due to its movementthrough the air when rotating and. the suction created at the. rear ofthe piston, results in an efi'ective pa:- sage of air through the pistonin quantities suincient to provide ample cooling of the. same- Ipreferably provide each piston with an. inner or head portion 84 whichis separate from the cylindrical side Wall or skirt of the piston. tointerrupt to some extent the passage of heat from the. piston. head tothe skirt or side wall. In the particular construction shown, seeparticularly Figs. 10-14, each piston has a tapering head portion '94,which is shaped to conform closely to the inner contour of. the taperinginner ends of the cylinders, to provide .a. small clearance between the.inner ends of the cylinders and the heads. of the pistons, as shown inFig. 3,. when the pistons are in their inner positions in. thecylinders. Also, the inner ends. 96 of the pistons are inclined tocorrespond to the inclination. or

taper of the valve 62, and the opposite sides. 91 of the piston head aresubstantially flat to. co.- operate with the flat faces ll of thecylinders.

The head 94 of the piston is preferably also. made hollow and is.provided with a plurality of webs 98 which are formed integral withandextend between. theopposite flat sides 91 of the piston head. Thesewebs servev the two-fold pur-- pose of reinforcing the hat sides of thepiston heads to prevent collapse or deformation of the same by thepressure of the compressed gas, and also of transferring heat to coolingair circulating. through the pistons. The piston heads also each have acentral, diametrically extending web or partition 99 which extendscrosswise of the webs. 98 and terminates at one end at a distance fromthe inner ends of the webs 98. This partition 99 extends from the head94 through the interior of the cylindrical. portion or skirt 95 and ispreferably. provided with an enlarged portionv the heat flow and resultsin higher tempera-' I whichhas a hole therein in which the piston pin45- is secured, for example, by means of set screws IOI, Fig. 11. Thepartition may be suitably reinforced by means of a bead I02, and theouter edges'may be provided with flanges I03. If desired, packingmaterial I04 may be provided between the flanges I03 and the'cylindricalportion or skirt 95.

The partition 99 also serves as a connectin member between the head'94of the piston and a cap member I05 between which the skirt 'portion' maybe secured. In the construction shown for this purpose, the partition 99is provided beyond the enlargement I00 thereof with segmental p01- tionsI06 or other enlargements to which the cap member I05 may be secured.This cap member has an-annular shouldered part adapted to engage theouter end of the skirt'portion 95,

the inner end of the skirt portion being seated on a correspondingannular shouldered portion ofthe head 94. Bolts or screws I09 extendthrough the cap member and engage threaded holes'in the segmental par-tsI06 of the partition 99 for firmly securing the skirt 95 to the head 94.

The skirt may be provided with piston rings H0 adjacent to the head 94.

The 'cap member 'is provided with an air inlet opening II2 on theleading side thereof and with an air discharge opening H3 at thetrailing side thereof, the openings being separated by a partition H4which forms substantially a continuation of the partition 99.Consequently, when the piston moves wtih the cylinder wheel in thedirection indicated by arrow ll5, in Fig. 10, it

will be obvious that air will flow into the outlet- I I2 and down alongthe piston on one side'of the partition 99, through the spaces betweenthe webs 98, around the inner end of the partition 99 in the piston headand upwardly on the other side thereof to the discharge opening H3. TheQ flow of air through the piston will be approxivalve matelyproportional to the speed of rotation of the cylinder wheel, and sincethe heat developed in the pistons is also approximately proportional tothe speed of rotation of the cylinder Wheel, very efilcient cooling ofthe pistons results at all speeds of operation of the machine;Theconstruction described has thefurther advantage that the differentparts of the pistons may be made of diiferent materials most suitablefor the particular parts. The contact'between the piston head and skirtresists rapid transfer of heat from the head to the piston, and heatinsulating washers or gaskets may be interposed between the head andskirt if desired.

By means of the construction described, 'a rapid flow of cooling airwill be forced through each piston because of the rapid movement of theends of the pistons through the surrounding air and because of thelocation of the inlet and dis-' is withdrawn from the piston heads. IThis results in withdrawing more heat from the pistons" than from thecylinders, which results in several advantages. In machines in whichlittle or no heat is removed directly from the pistons,

such, heat is dissipated mostly or entirely through passage. from thepistons to the cylinders,

through the oil fllm between the pistons and cylinders. This oil filmhas a'high resistance to the passage of heat therethrough, which retardswill be transferred to the relatively cooler piston= heads than to theadjacent portionsof the cylinders. Consequently, this reduces the amountof cooling of the head portions of the cylinders that would otherwise berequired, and this, in turn, makes it possible to bring the tapered headportions of the cylinders closely together, as is clearly shown in Figs.6-8. This, in turn, makes it possible to provide a relatively largenumber of cylinders in the cylinder wheel and at the same time to havethe tapering bore in the central portion of the cylinder wheel of smalldiameter, thus permitting the use of a relatively small valve and,consequently low lineal speeds of the central-Ibore of the cylinderWheel relatively to the Another advantage of removing more heat from thepistons than from the cylinders is that iffor any reason'the machinebecomes heated to high temperatures by maintaining the cylinder headscooler than the adjacent portions of the cylinders'the cylinders willexpand,-due to heat, to a greater'extent than the pistons, thusavoidingthe seizing of the pistons in the cylinders, which takes placein machines in which the pistons become heated to higher temperaturesthan the cylinders. This fact in turn makes it possible, in theconstruction of my improved machine, to allow for smaller clearancesbetween the'pistons and cylinders than is now standard practice. Thisadds to the efficiency of these machines'since less leakage of gas pastthe pis-' V a machine before the cylinders become worn to such an extentas to require reboring of the cylinders or the-installation of newpistons.

Consequently, it is obvious that by removing more heat from the pistonsthan from the cylinders, a very efiicient machine can be constructed ofsmaller size and weight'for a given capacity than would be the case ifheat were removed mainly through the cylinders. Also, the heat of thepistons is more efficiently and quickly removed from the piston heads,since the interiors of the heads will be dry, so that cooling air willcontact directly with the dry metal surfaces in the interiors of thepistons, which results in a much more rapid transfer of heat to" thecooling air than is the cas in machines in'which the heat of the pistonsis transferred through an oil film to the cylinder walls before it canbe removed by the cooling fluid. Furthermore, no circulating pump or fanis required for circulating the cooling. air through the pistons, thusavoiding the necessity for auxiliary cooling equipment and avoiding thepossibility of'damageto the machine, in the event of failure of suchequipment. It will also be noted that the machine shown is soconstructed that the caps I05 of the pistons extend'beyond the outerperiphery of the cylinder wheel even when the pistons are in their 4.The. air is impelled in the housing of the compressor in the directionindicated the arrows in Fig. 4, and since the pistons extend beyondtheperiphery of the cylinder wheel to the maximum extent in the lowerportion of thahousing, they will produce a current of air thereindirected: toward the discharge opening H8. This positive.- discharge ofair fromthe housing will result in a. corresponding in-flow of airthrough the. openings H1, and this incoming air consequently flowsagainst. the middle: portions of the cylinder wheel, where the greatestamount of heatiszgenerated.

It will be seen that the housing completely encloses the machine andthat all. the cooling air enters. the air inlet openings ll-l.Consequently, if desired, the cooling air admitted to the housing may befiltered orotherwise freed from dust and abrasive particles, so thatnodust or particles will settle on the parts of the pistons which extendout of the cylinders.

I have shown by way of example on Figs. 1 and 3, how air filtering meansmay be readily applied to th housing shown in the drawings. For example,the outer edges of. the: two: inner flanges 22: on each end. of themachine are covered by means of a plate I20 having an opening I 2|therein, and an air filter may be arranged on the outer face of theplate I20 across the. opening l2l, such for example: as an air filtercartridge I22, containing any usual or suitable filtermass. Thiscartridge may be held in a frame I24 secured to the plate I20, Thisframe may, for example, be open at one side, such as the right hand sidein Fig. 1:, so that the filter cartridge in can.

be readily inserted and removed for cleaning or for replacing withanother cartridge. Consequently, during rotation of the cylinder wheel,

air will be drawn through the air filters into the space between the twoinner flanges 22 and will then pass through the air inlet. openings Illinto the interior of the housing. Any other means for filtering. airentering the housing may be provided, or if desired, suchfiltering meansmay beomitted- Any suitable means may be provided for applying lubricantto the relatively movable parts of the machine, no lubricating systembeing shown. Since the machine shown will tend to throw lubricant out bycentrifugal force, it may be collected in the housing of the machine anddrained from the. bottom of the housing through.

a drain hole: I28, Fig. 4.

While I prefer to construct .the machine with revolving cylinders andmaster rings and stationary bearing supports and valve, yet it will beobvious that certain features of this invention seers-7etor'isreciprocable in said cylinders, apair of rings atv oppositesides or said. cylinders: and mounted to rotate about an axisspa'cedfrom the aidsofrctation of said cylinders, connecting said ring. andsaid cylinders for maintaining relative positions of said ring and saidcylinders, and a pair oi rods for each piston pivotally connected tosaid rings and to a piston, said rods being arranged to extend in planessubstantially parallel with. the axes of said pistons and: cylinderswhen said rods transmit the greatest force to said pistons.

2-, A. machine having a group of cylinders arranged. about an axis, avalve arranged said. axis, one of which is rotatable relatively to theother about said axis, pistonsv arranged to reciprocate in cylinders, apair of piston rods for each piston and extending along oppos te sidesof said cylinders, and means; for im- -parting reciprocatory motion tosaid pistons through said rods and including a pair oi? master rings,one at. eachside of said group of cylinders,. and journallcdeccentrically with reference to said axis and to which said piston rodsare connected, connecting, said master ring and said group of cylinders,said rods being so arranged relatively to cylinders that said rods andthe longitudinal centers oi said pistons are in the same plane slightlybefore said pistons complete their compression strokes 3-. A. machinehaving a group of cylinders arranged radially about an axis, a valvearran ed in said: axis, one of which. is rotatable relatively to theother about said axis, pistons arranged. to reciprocate in said.cylinders, a pair of piston rods for each piston and extending alongopposite sides of said. cylinders, and means for imparting reciprocatorymotion to said pistons through said rods and. including a pair of ast rrings, one at each side of said. group of cylinders, and iournalledeccentricall'y with reference to said axis and to which said piston rodsare connected, links connecting said master ring and said. group of.cylinders. said rods being so arranged relatively to their cylindersthat said rods pass through radial planes extending through thelongitudinal centers of the pistons twice during and. before completionof their compression strokes.

4. A machine having a piston arranged to re ciprocate in a cylinderrotatable about an axis extending transversely of the cylinder; a ringmounted to rotate about an axis spaced from said first mentioned axis, alink connecting said 1 ring and said piston, and a rod pivotally conwhencompressed fi'uid is discharged from said cylinder...

5. A machine having a pistonv arranged to reciprocate in a cylinderrotatable about an axis extending transversely of the longitudinalcenter line. of the cylinder, 2. ring. mounted to rotate about an. axisspaced, from said first mentioned axis, a link connecting said ring andsaid cylinder, and a rod pivotally connected with said ring and said.piston, the pivotal connections of said rod with said. ring and saidpiston being so arranged that said rod. will pass. through a radial.plane including said axis of rotation of said cylinder and the centerline of said cylinder slightly before said piston completes itscompressionstroke.

, 6. A machine having a piston arranged to reciprocate in a cylinderrotatable about an axis extending transversely of the longitudinalcenter line of the cylinder, a ringmounted to rotate about an axisspaced from said first mentioned axis, a link connecting said ringandsaid cylinder, and a rod pivotally connected with said rin and saidpiston, the pivotal connections of said rod with said ring and. saidpiston being so arranged that said piston and said rod pass through wradial planes including said axis of rotation of said cylinder and thecenter line of said cylinder during and before the completion of thecompression stroke of said piston.

'7. A machine having a group of cylinders arranged radially about anaxis, a valve arranged in said axis, one of which is rotatablerelatively to theother about said axis, pistons arranged to reciprocatein said cylinders, means for imparting reciprocatory motion to saidpistons, the inher ends of said cylinders having ports which areelongated in the direction of'said axis and arranged to communicate withports in said valve, said cylinders having converging substantially fiatsides at their inner ends which terminate at the elongated sides of saidcylinder ports.

8. A machine having a group of cylinders arranged radially about anaxis, a valve arranged in said axis, one of which is rotatablerelatively to the other about said axis, pistons arranged to'reciprocate in said cylinders, means for imparting reciprocatory motionto said pistons, the inner ends of said cylinders having ports whichareelongated in the direction of said axis, and arranged to communicatewith ports in said valve, said cylinders having converging substantiallyflat sides at their enner ends which terminate at the elongated sides ofsaid cylinder ports, said pistons having flat sides at their inner endsto enter between said flat sides of said cylinders.

9. In a machine of the revolving substantially radial cylinder typehaving pistons arranged to reciprocate in the cylinders, a ringrotatable eccentrically with reference to said cylinders, piston rodsconnecting said ring with said pistons for imparting reciprocatorymotion with said pistons, each piston rod extending along a side i of acylinder and being of vane-shaped cross section to direct cooling airtoward its cylinder during the rotation of the same.

10. In a machine of the revolving substantially radial cylinder typehaving pistons 21- piston links connecting said-ring and said pis-' tonsfor imparting reciprocatory motion to said pistons, and a unitarybearing support on which both said cylinder wheel and said ring arejournalled, whereby the stresses resulting from the reactions betweensaid cylinders and said pistons are transmitted to said bearing support.

' 12. In a machine of the substantially radial cylinder type including acylinder wheel mounted to rotate about an axis, pistons reciprocable inthe cylinders of said wheel, a pair of rings mounted on opposite sidesof said cylinder wheel to rotate eccentrically with reference to saidcylinder wheel, piston rods having pivotal connections with said wheeland said pistons for imparting reciprocatory motions to said pistons,and a pair of bearing supports, one arranged at each side of saidcylinder wheel, each bearing support having said cylinder wheel and saidring journalled 10 thereon, each ofsaid bearing supports being ofintegral structure,.and a frame on which said bearing supports arerigidly mounted.

13. In a machine of the substantially radial cylinder type including acylinder wheel mounted to rotate about an axis, pistons reciprocable inthe cylinders of said wheel, a ring at each side of said cylinder ringmounted to rotate eccentrically with reference to said wheel, a pair ofpiston rods at opposite sides of each cylinder and connecting said ringsand a piston for imparting reciprocatory motion to said pistons, and aplurality of links ivotally connecting said ring and said cylinder wheelto transmit rotary motion from one to the other,

14. In a machine of the substantially radial cylinder type including acylinder wheel mounted to rotate about an axis, pistons reciprocable inthe cylinders of said wheel, a pair of rings mounted on opposite sidesof said cylinder wheel to rotate eccentrically with reference to saidcylinder wheel, a pair of piston rods at opposite sides of each cylinderand having pivotal connections with said wheel and said pistons forimparting reciprocatory motions to said pistons, and a plurality oflinks pivotally connecting each ring with said cylinder wheel to connectsaid rings and wheel to rotate together about their own axes.

15. A machine having a group of cylinders arranged substantiallyradially and rotatably about an axis, a stationary part on which saidgroup of cylinders ibears, pistons arranged to reciprocate in saidcylinders, said cylinders terminating at their head portions in afrusto-conical bore, a stationary valve member having a frusto-conicalportion and seated in said bore, and yielding means acting on said valvemember and said stationary part for urging said valve in a direction toseat in said bore.

ranged substantially radially and rotatably about an axis, a stationarypart on which said group of cylinders bears, pistons arranged toreciprocate in said cylinders, said cylinders terminating at their headportions in a frusto-conical bore, a stationary valve member having afrusto-conical portion and seated in said bore, yielding means acting onsaid valve member and said stationary part for urging said valve in adirection to seat in said bore, and means for varying the force exertedby said yielding means in a direction to seat said valve.

17. In a machine of the revolving substantially radial cylinder typehaving pistons arranged to reciprocate in the cylinders, rings atopposite sides of said revoluble cylinders and mounted to rotateeccentrically with reference to said cylinders, a series of fins on saidcylinders substantially concentric with the axis of rotation of saidcylinders, a pair of piston rods connecting each piston with said ringsat opposite sides of a cylinder, said piston rods having vane-shapedportions for directing air currents against opposite sides oi saidcylinder and between said fins.

18, A multi-cylinder compressor of the substantially radial revolvingcylinder type including a 16. A machine having a group of cylindersarcylinder wheel having a plurality of substantially radial cylindersformed therein, said cylinder Wheel including a central web formedintegral with said cylinders, a series of fins extendin outwardly fromsaid web and said cylinders, pistons arranged to reciprocate in saidcylinders, rings at opposite sides of said cylinder wheel mounted torotate eccentrically relatively to said cylinder wheel, and piston rodsconnecting said rings and said pistons for reciprocating said pistonsand having parts thereon for directing air currents against oppositesides of said cylinder wheel.

19. In a machine of the substantially radial cylinder type including acylinder wheel mounted to rotate about an axis, pistons reciprocable inthe cylinders of said wheel, a ring. mounted to rotate eccentricallywith reference to said wheel, piston eds conne tin said r and i p stonsfor impart g ec p oc ory m tion to said, pistons, and a ni y bear ng prt qnwhich, both said cylinder wheel andsaid ring are. journalled, wh rby t e stresses esu t ng i om the. reactio -S between said cy md rs andaid p stons a e transmitted to said bearing support, said cylinder Wheelhaving a substantially frusto-conical hub having, pa s w th whi a d cyinders. ommuni ate, a s iona alv havin a substant a y frustoon c l. po tn fi t ng in sa d hub, and yie din a s o n cting said va v andsaidvbearing s pport for urging. said valve into seating relation tosaid hub.

JOSEPH S. PARENTI.

